Piston ring



Mach 31, i931. 4 HEDEPUTY 1,798,458

PISTON RING Filed Sept. 12, 1927 Gnou-Ma Patented Mar. 3l, 1931 PATENTOFFICE HORACE E. DEPUTY, OF LONG BEACH, WASHINGTON PISTON RINGApplication filed September 12, 1927. Serial No. 219,019.

This invention relates to piston rings and particularly to piston ringsfor internal combustion engine use.

An object of the invention is to mount a V piston ring upon a pistonworking in a cylinder Without initial compression of the ring by Contactwith the .cylinder wall and to admit compressed gases into the pistonring groove on the pressure and `explosion strokes of the piston toexpand said ring into sealing engagement with the cylinder wall solelyby the outward pressure of such gases.

Another object of the invention is to form a piston ring with one ormore slots extending ,1l substantially radially through said ring andproviding for the positive discharge into the inner portion of a pistoncarrying said ring of such excess lubricant as accumulates a'djacent tosaid ring.

Still another object is to cut away the outer face of the aforesaidpiston ring between said slots and the edge of the ring remote from thecombustion chamber to facilitate the delivery of lubricant from inadvance of said ring through said slots, on the down stroke of thepiston.

These and various other objects the invention attains by theconstruction hereinafter described and illustrated in the accompanyingdrawing, wherein:

Figure 1 is a vertical sectional view of an engine cylinder and piston,the latter of which is equipped with sealing rings embodying theherein-disclosed features.

Figure 2 is a top view of one 'of said rings.

Figures 3 and 4 are fragmentary perspective views of said ring. Figure 5is a fragmentary side view ofthe ring showing the overlapped split ends0 thereof.

Figure 6 is a fragmentary bottom View of another portion of said ring.

F igure`7 is a fragmentary enlargement of a portion of Figure 1, showingin cross section 3 the ring nearest to the crank case and the adjacentportions of the 4piston and cylinder walls.

In these views the reference character 1 designates an internalcombustion engine '0 cylinder, and 2 a piston working in sai-d cylinder,and having annular grooves 3 receiving split sealing rings 4, havingtheir ends over lapped. Diverging from common practice, said overlappedends form-a series of interlitting steps 4a which minimize leakage by 55compelling any gases iiowing between said ends to make at least fourright angle turns. The number of such rings used in any piston may besuited to' the particular installation, three being shown in thedisclosed emhodinient of the invention. The inner face of each ring ismachined to form annular steps or offsets 5, 6, 7 and the bottoms ofthepiston grooves receiving said rings are correspondingly machined, as isbest seen in Figure 7.

The arrangement is preferably such as to form a slight clearance betweenthe stepped bottom face of each groove and the stepped inner face of thecorresponding ring, when the latter is expanded, and also provides aslight clearance between the stepped end face of each ring and thecorresponding Wall of each groove. This facilitates admission of gasesbetween the piston and ring when such gases are under compression in thecombustion chamber. The effect of the described stepped construction isto increase the sealing eiliciency of the rings and maintain a highercompression co-ellicient than is permitted by rings of the usualrectangular cross-section.

In the practice heretofore common, the maintenance of a sealingengagement of the piston rings of internal combustion engines withthe'cylinders of sai-d engines has been achieved primarily by formingthe rings of a normal diameter exceeding that ofthe cylinder bore, thusnecessitating a certain compression of the rings upon their insertion insaid bore and creating an expansive pressure of said rings upon the wallof said bore. Such G0 practice has necessitated the employment of ringssufliciently heavy to resiliently exert the desired sealing pressureupon the cylinder wall, and in some instances such rings have beentapered from their mid-portions to their ends. The present constructiondiverges from such prior practice in fashioning a piston ring to anormal (or unsprung) diameterequal to or slightly less than that of thecylinder bore to receive said ring and in de- 101i slots into thegrooves 3. That one of said.

pending solely on the expansive action upon the ring of a mixtureundergoing compression by the piston or of the explosion productsdriving the piston, to establish sealing engagement of the ring with acylinder wall. By thus avoiding reliance on the resilient nature of theringr to establish its sealing contact with the cylinder, it becomesfeasible to use a considerably lighter ring than heretofore and to makethe cross sectional area of the ring a constant from end to end of thering. Also assembly in a cylinder of a piston equipped with my improvedrings is considerably facilitated as compared With prior practice, sincesaid rings require no compression to permit their insertion in thecylinder bore.

As the piston undergoes its downward stroke, the' piston rings act toscrape any excess of lubricant from the cylinder wall, and it isdesirable to continuously remove any such excess of lubricant from` inadvance of said rings to prevent such lubricant finding its way to thecombustion chamber. Thus the ring farthest from the 'combustion chamber(and if desired, each of the rings) is formed adjacent to its Wider endface with a plurality of circumferentially elongated slots 8 extendingradially through the rings and any lubricant accumulating in advance ofthe ring may find its way through such grooves which is farthest fromthe combustion chamber has a lubricant discharge passage 9 leadingtherefrom through the piston wall, and 'if desired a similar passage mayextend from each of the grooves '3.

To facilitate access of the lubricant to the slots 8 from in advance ofthe piston rings, on the explosion stroke of the piston, it is preferredto annularly cut away the outer faces of the rings from said slots tothe wider end faces of the rings, as 4indicated at l0, whereby anylubricant accumulating in aldvance of said rings is delivered into saids ots. i

While it will be apparent that the illustrated embodiments of myinvention herein disclosed are well calculated to adequately fulfill theobjects and advantages primarily stated, it is to be understood that theinvention is susceptible to variation, modification and change withinthe spirit and scope of thcJ subjoined claims.

What I claim is:

l. The combination with a cylinder and a piston Working in saidcylinder, formed with an annular groove having an annularly steppedbottom, of a piston ring formed as a split annulus fitted in said grooveand having its upper face stepped in complementary relation to thegroove bottom, said ring having a normally unexpanded exterior diameterless than the diameter of the cylinder wall, and provided with means fortransmitting lubricant from the cylinder Wall to the interior of thering when the ring is expanded by pressure from above the piston rmglnto engagement with said wall.

2. The combination of a cylinder and a piston working in said cylinderand formed with a peripheral groove, of a piston ring formed as a splitannulus having its normal outside diameter slightly less than thediameter of the cylinder bore and its normal inside diameter greaterthan the distance between the opposite portions of the inner wall ofsaid groove, whereby the ring will normally seat in said groove out ofcontact with both the cylinder wall and the inner wall of the pistongroove, the upper and inner portions of-said ring being arranged to beengaged by gases under pressure from within the cyl nder to expand thering into engagement with the'cylinder Wall, the central portion ofthering being provided with radial apertures, and the lower portion of thering being arranged to scrape lubricant from the piston wall while thering is expanded and guido such lubricant to said apertures.

In witness whereof I hereunto set my hand.

HORACE E. DEPUTY.

